The purpose of this study was to evaluate the molecular relatedness of clinical isolates of vancomycin-resistant enterococci (VRE) collected from patients of the Clinic for Infectious and Tropical Diseases in Belgrade. Among 40 isolates available for the investigation, 36 were identified as Enterococcus faecium, whereas 2 were Enterococcus faecalis and Enterococcus raffinosus, respectively. Pulsed-field gel electrophoresis (PFGE) typing revealed 21 strain types, comprising 7 clusters which contained at least two isolates and 14 unique PFGE patterns. Although we searched for pathogenicity factor genes (gelE, cylB, asa1, efaAfs, esp, cpd, cob) in representatives of all macro-restriction patterns, they have been confirmed in only one clone of E. faecalis. Genes esp and hyl, commonly found in E. faecium, were yilded in 10 macro-restriction patterns of this species, and their presence could not be ascribed to clonally related strains (p = 0.05). All VRE isolates were multiresistant and positive for vanA gene. Twenty strains of VRE and 6 clusters obtained from Intensive care unit (ICU) are proof of intensive transmission of these microorganisms at this department. The results of this study suggest wide genotypic variability among the clinical VRE isolates, but also intrahospital dissemination of some of them.
Methicillin-resistant Staphylococcus aureus (MRSA) emerged as one of the most important causes of hospital-acquired bloodstream infections (BSIs), especially the multidrug resistant clones. The aim of the present study was to compare prevalence and resistance patterns of MRSA bacteremia in the major tertiary-care academic and referral center in Serbia before and after implementing an active antimicrobial resistance (AMR) surveillance. Laboratory-based before-after study was conducted during a two-year period (January 2012 to December 2013) in Clinical Centre of Serbia. Isolation and identification of bacterial strains were done following standard microbiological procedures. During the AMR surveillance, nearly twice more bloodstream samples were collected compared to the year without surveillance (1,528 vs. 855). In total, 43 isolates of MRSA were identified. MRSA was significantly more prevalent during the AMR surveillance compared to the previous year [14 (66.7%) to 29 (76.3%); P = 0.046]. During the AMR surveillance, MRSA more frequently originated from medical departments compared to intensive care unit, surgical department, and internal medicine (P = 0.027) indicating increasing MRSA infections in patients with less severe clinical condition and no apparent risk factors. Higher prevalence of MRSA and its lower susceptibility to erythromycin were revealed by implementation of active AMR surveillance, which may reflect more thoughtful collection of bloodstream samples from patients with suspected BSI.